On Thu, May 14, 2020 at 09:07:29AM -0300, SysAdmin EM wrote:
> postfix-out/smtp[12931]: E30639204ED: to=<m_snyder...@hotmail.com>,
> relay=hotmail-com.olc.protection.outlook.com[104.47.124.33]:25,
> delay=1.4, delays=0.08/0/1.4/0, dsn=5.5.4, status=bounced
> (host hotmail-com.olc.protection.outlook.com[104.47.124.33]
> refused to talk to me: 501 5.5.4 Invalid domain name
> [HK2APC01FT037.eop-APC01.prod.protection.outlook.com])
The "refused to talk me" prefix means that the delivery attempt was
rejected either in the server's SMTP greeting or the EHLO response,
however the actual response also contains a 5.5.4 DSN status code,
which would only be appropriate in response to EHLO. Therefore,
the pattern was:
C -> S: TCP SYN
S -> C: TCP SYN ACK
C -> S: ACK
S -> C: 220 <server-hostnname> ESMTP ... <CRLF>
C -> S: EHLO <your-hostname> <CRLF>
S -> C: 501 5.5.4 Invalid domain name <CRLF>
The 501 code suggests a syntax issue, from which it seems that Microsoft
are claiming that your SMTP EHLO name is malformed.
Therefore, take a close look at your "smtp_helo_name" and "myhostname"
settings.
--
Viktor.
